Fleets use the fixed for several reasons. The fixed is lighter, stronger, and cheaper. Also, they don't risk Gomer crushing the reefer unit, or folding the front of the trailer on a tight turn. Gomer will do that, but with a fixed fifth wheel, at least he's limited to dangling the mirror, front bumper, and poking holes in any side fairing, and of course bending a rim or two, and tearing a back door off on a loading dock.
Some Companies haul the same freight, so their weight distribution is set. If you are going to haul different trailers, or different loads all the time, you want a slider.
I don't know the cost, but I can imagine those things are not easy to get off. :block:
When you shorten the space between the tractor and trailer, you will get better fuel economy. A slider can make the difference on some yards with real tight space, and save you from eating your own organs. I'll run long on some areas with washboard roads. It's more comfortable, and easier on my load. Even with smaller tractors, I like having a slider, because it offers me options.
When I got to use my first air slider...I felt like a top hand, even though I look like Gomer.
Roadhog mentioned some valid reasons why some carriers may prefer a fixed fifth wheel rather than a sliding fifth wheel. Personally, I prefer a sliding fifth wheel. It is rare that I need to move it, but can be convenient when the need arises. It has been a while since I priced a fifth wheel, but you can go to Holland's website and check prices. Just do a search for semi fifth wheels. Of course, that won't include labor costs. You could find one at a salvage yard for much less than new.
A friend of mine replaced his fifth wheel a few months ago. With the help of his son in law they changed it out on a Saturday. But then, it was already a slider. I would expect that you would need to drill holes in the frame if you replace a fixed fifth wheel with a slider. If it were me I would prefer buying a truck with a slider already installed. I found a truck that I considered purchasing a couple of years ago that had a fixed fifth wheel. After checking the price to put a slider on it I decided to not purchase it. I don't recall the price to change it over.
You could probably save some money by buying one with a fixed fifth wheel. Most carriers who lease on owner operators require a sliding fifth wheel.
Gman made some pretty valid points. Most really have no need for a slider for most situations, especially with dry vans.
One thing seems many fail to do is to maintain a slider properly. After winter, get that unit thoroughly cleaned out, dryed, and lubed. Repaint the rusting slider (and while there, clean and spot paint those rusting spots on the frame rail). A solid cleaning, a steel brush, some compressed air, and Rustoleum paint works wonders for that. Move that slider forward all the way and rearward all the way and with each move, spray something like a metal protector / lubricant on the slider carrier. I am not a big user of Amsoil, but they make a real great product just for that purpose called HD Metal Protector. If you do this simple process a couple of times a year, your slider will stay virtually brand new.
A superior driver uses superior judgement to avoid situations which require superior skill.